Call to undefined function mb_strtoupper()

$ yum info php-mbstring
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirror.neolabs.kz
 * epel: mirror.nus.edu.sg
 * extras: mirror.neolabs.kz
 * updates: mirror.neolabs.kz
Installed Packages
Name        : php-mbstring
Arch        : i686
Version     : 5.3.14
Release     : 1.el6
Size        : 3.9 M
Repo        : installed
From repo   : CentALT
Summary     : A module for PHP applications which need multi-byte string handling
URL         : http://www.php.net/
License     : PHP
Description : The php-mbstring package contains a dynamic shared object that will add
            : support for multi-byte string handling to PHP.

$ cat /etc/redhat-release 
CentOS release 6.3 (Final)

root@server1 [~]# rpm -ivh /root/php-mbstring-5.3.3-3.el6_2.8.x86_64.rpm
error: Failed dependencies:
       php-common = 5.3.3-3.el6_2.8 is needed by php-mbstring-5.3.3-3.el6_2.8.x86_64

rpm -qa | grep php